title: Interaction of curcumin with intravenous immunoglobulin: a fluorescence quenching and Fourier transformation infrared spectroscopy study.
abstract: The interaction of curcumin with intravenous immunoglobulin (IVIG) mainly composed of immune gamma globulin (IgG) was studied in vitro by spectroscopic methods including fluorescence spectroscopy and Fourier transformation infrared (FTIR) spectroscopy. Docking was used to calculate the interaction mode between curcumin and IVIG. The binding parameters for the reaction were calculated according to the Sips equation, which suggested that the binding of IVIG to curcumin was characterized by two binding sites with the average affinity constant K(o) at 1.170 x 10(4) M(-1) (296 K), and it was a non-specific and weak drug-protein interaction. The secondary structure compositions of free IVIG and its curcumin complexes were calculated by the FTIR difference spectra, self-deconvolution, second derivative resolution enhancement and the curve-fitting procedures of amide I band. The observed spectral changes indicate a partial unfolding of the protein structure, but the typical beta structural conformation of IVIG is still retained. The average binding distance between curcumin and the chromophore of IVIG (5.57 nm) was obtained using the theory of Förster energy transfer. IVIG can serve as transport protein (carrier) for curcumin.
authors.affiliation: State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, PR China. ychliu001@163.com
authors.forename: Yongchun
authors.initials: Y
authors.lastname: Liu
authors.forename: Zhengyin
authors.initials: Z
authors.lastname: Yang
authors.forename: Juan
authors.initials: J
authors.lastname: Du
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Yao
authors.forename: Ruixia
authors.initials: R
authors.lastname: Lei
authors.forename: Xudong
authors.initials: X
authors.lastname: Zheng
authors.forename: Jianning
authors.initials: J
authors.lastname: Liu
authors.forename: Huaisheng
authors.initials: H
authors.lastname: Hu
authors.forename: Hong
authors.initials: H
authors.lastname: Li
mesh_terms: D001665:Binding Sites; D030024:Curcuma; D003474:Curcumin / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D004347:Drug Interactions; D005453:Fluorescence; D006801:Humans; D016756:Immunoglobulins, Intravenous / Q000737:chemistry / Q000276:immunology / Q000378:metabolism* / Q000494:pharmacology; D007167:Immunotherapy; D008956:Models, Chemical; D008517:Phytotherapy; D011485:Protein Binding; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D016756:Immunoglobulins, Intravenous; D003474:Curcumin